The known arrangement according to JP 61229977 A has a linear actuating member having an actuating element consisting of an alloy with impressed shape memory. It is equipped with a moving piston and is connected at both ends to a current source. When current is supplied, the actuating element can be adjusted in the axial direction of the piston by heating and subsequent cooling. For the return movement of the actuating element into its starting position, a cylindrical spring is attached to the same.
In the arrangement which is known through DE 31 40 472 C2, the working piston of a temperature-dependent expansion body and hence also the tappet of a valve are moved by the effect of electric current. An expansion body of this kind comprises a hermetically sealed metallic pot, in which there is disposed a material which changes its volume in dependence on the temperature. The working piston projects into this material with maintenance of the hermetically sealed closure, which working piston, upon heating, is forced out of the pot and, upon cooling, is forced back into the same by a counterforce. Attached to the pot of the temperature-dependent expansion body is, in this arrangement, an electrical resistance as the heating element. A signal delivered, for example, by a thermostat causes the resistance to be supplied with current. As a result of the heat which is then generated, the working piston of the expansion body is adjusted. The tappet of the valve, which valve, for example, in the rest position is closed, is thereby relieved of load and moved by a restoring spring in the “valve opening” direction. Correspondingly constructed arrangements generally work satisfactorily. Because of the relatively large axial length of the expansion body, they often, however, have disturbingly large dimensions. The expansion body is, moreover, a complex and therefore expensive structural part.